Extrusion



FIG. 1 is a fragmentary perspective view of a cross-section of the first embodiment of our design for an extrusion, the extrusion having the same cross-sectional shape throughout its length, and being of indefinite length;

FIG. 2 is a front view thereof;

FIG. 3 is a fragmentary perspective view of a cross-section of the second embodiment of our design for an extrusion, the extrusion having the same cross-sectional shape throughout its length, and being of indefinite length; and,

FIG. 4 is a front view thereof. 

The ornamental design for an extrusion, as shown and described. 